1. Field of the Invention
The present invention relates to an image processing apparatus having a function of performing an image quality correction process on an image signal, an image display and an image processing method.
2. Description of the Related Art
Typically, apparatuses such as television receivers, VTRs (Video Tape Recorders), digital cameras, television cameras or printers have an image processing function which makes an image quality correction to an input image, and outputs the input image (for example, functions such as luminance or contrast control, and contour correction). Such a function is effectively applied mainly to a totally dark and low-contrast image or a blurred image.
Among these functions, in general, the contrast control is performed by correcting a gamma curve which represents so-called gamma characteristics. In this case, the amount of correction which is set at each luminance (signal) level at the time of correcting the gamma curve is called gain.
For example, in Japanese Unexamined Patent Application Publication Nos. 2002-366121, 2004-40808 and 2004-282377, there are disclosed image processing techniques in which the luminance distribution of an input image is detected as a histogram distribution, and then image processing such as contrast control is performed on the input image on the basis of the histogram distribution. In these techniques, when specifically the gain is set to be large at a luminance level with a high frequency value, the overall contrast can be effectively improved.